O like oblique

O as in Oblique

Your have external obliques and internal obliques.  The external oblique is the largest muscle closest to the surface on your side.  Its main job is to pull the chest downward and compress the abdominal cavity.  The internal obliques, on the other hand, have two main jobs.  First, it counteracts the diaphragm (the muscle that contracts excessively when you hiccup) so that you can exhale.  Second, it allows you to rotate and bend from your trunk.

This is also the area of the body where the famous “love handles” develop, which people work so hard to eradicate.  In the front of the abdomen, there is a major muscle called the rectus abdominis, which stretches from the pubis to the ribs.  On either side of the rectus

abdominis, right at the hips, the internal obliques are located.  The external obliques are higher, on either side of the rectus abdominis, and start at the rib cage.

Anytime a person twists their body, both sets of obliques work, but the action of each muscle depends on which way a person twists.  For example, when you twist to the left your left internal oblique gets a stretch, as well as your right external oblique muscle.  It’s easy to feel this with the slight pull on the rib cage and chest that occurs when a person engages in a twist.

There are many exercises to work on your obliques, some which you will find in the NIMBLE book, but here's another easy one.  Use a broomstick or an umbrella if you don't have a rod of any kind!